This invention relates to safety apparatus and, more particularly, to a thermally responsive slam shut valve assembly.
In a building connected to a gas line, there is always the danger of a fire. The heat of the fire can cause the failure of non-metallic parts, such as diaphragms, in meters or regulators in the line. The failure of these parts causes a dramatic increase in the gas flow rate, feeding the fire and raising the temperature to such an extent as to cause the burning the subsequent total failure of the meter or regulator, which is typically constructed of aluminum. It is therefore an object of this invention to provide an arrangement sensitive to elevated temperatures for shutting off the flow of gas in a gas line prior to such failure.
There have been a number of attempts in the past to provide such an arrangement whereby a fusible link holds a valve member in the open position until the temperature rises to such an extent that the link softens to allow the valve to close. See, for example, U.S. Pat. Nos. 288,271; 466,022; 1,956,858; and 2,903,005. However, all of these arrangements require some modification to the existing gas line and/or connections. It is therefore another object of this invention to provide a thermally responsive slam shut value assembly which does not require any modification to the gas line and/or connection in which the assembly is installed.